Connexions is a non-profit website billed as a "place to view and share educational material made of small knowledge chunks called modules that can be organized as courses, books, reports, etc." All materials are Creative Commons Attribution licensed.
Currently, 3845 modules are available, including 201 classified as Social Science. Most seem to focus on Education, although Linguistics and Cognitive Science are strong, as well.
Connexions is based at Rice University, a school at the forefront of adapting (and adopting) information technology to the academic community.